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Rick Edgecombe 1d62c65372 x86/shstk: Support WRSS for userspace
For the current shadow stack implementation, shadow stacks contents can't
easily be provisioned with arbitrary data. This property helps apps
protect themselves better, but also restricts any potential apps that may
want to do exotic things at the expense of a little security.

The x86 shadow stack feature introduces a new instruction, WRSS, which
can be enabled to write directly to shadow stack memory from userspace.
Allow it to get enabled via the prctl interface.

Only enable the userspace WRSS instruction, which allows writes to
userspace shadow stacks from userspace. Do not allow it to be enabled
independently of shadow stack, as HW does not support using WRSS when
shadow stack is disabled.

>From a fault handler perspective, WRSS will behave very similar to WRUSS,
which is treated like a user access from a #PF err code perspective.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-36-rick.p.edgecombe%40intel.com
2023-08-02 15:01:51 -07:00
arch x86/shstk: Support WRSS for userspace 2023-08-02 15:01:51 -07:00
block block-6.5-2023-07-03 2023-07-03 18:48:38 -07:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto This update includes the following changes: 2023-06-30 21:27:13 -07:00
Documentation Documentation/x86: Add CET shadow stack description 2023-08-02 15:01:50 -07:00
drivers Fixes for pci_clean_master, error handling in driver inits, and various 2023-07-09 09:35:51 -07:00
fs mm: Introduce VM_SHADOW_STACK for shadow stack memory 2023-07-11 14:12:19 -07:00
include x86/shstk: Introduce map_shadow_stack syscall 2023-08-02 15:01:51 -07:00
init Kbuild updates for v6.5 2023-07-01 09:24:31 -07:00
io_uring io_uring-6.5-2023-07-03 2023-07-03 18:43:10 -07:00
ipc mm: Re-introduce vm_flags to do_mmap() 2023-07-11 14:12:18 -07:00
kernel x86/shstk: Introduce map_shadow_stack syscall 2023-08-02 15:01:51 -07:00
lib 16 hotfixes. Six are cc:stable and the remainder address post-6.4 issues. 2023-07-08 14:30:25 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: Don't allow write GUPs to shadow stack memory 2023-08-02 15:01:20 -07:00
net Including fixes from bluetooth, bpf and wireguard. 2023-07-05 15:44:45 -07:00
rust rust: error: impl Debug for Error with errname() integration 2023-06-13 01:24:42 +02:00
samples Including fixes from bluetooth, bpf and wireguard. 2023-07-05 15:44:45 -07:00
scripts A half-dozen late arriving docs patches. They are mostly fixes, but we 2023-07-06 22:15:38 -07:00
security + Bug Fixes 2023-07-07 09:55:31 -07:00
sound sound fixes for 6.5-rc1 2023-07-07 15:40:17 -07:00
tools perf tools changes and fixes for v6.5: 2nd batch 2023-07-08 10:21:51 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM64: 2023-07-03 15:32:22 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Revert ".gitignore: ignore *.cover and *.mbx" 2023-07-04 15:05:12 -07:00
.mailmap 16 hotfixes. Six are cc:stable and the remainder address post-6.4 issues. 2023-07-08 14:30:25 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS - Address -Wmissing-prototype warnings 2023-06-26 16:43:54 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS 2: Electric Boogaloo 2023-07-09 10:29:53 -07:00
Makefile Linux 6.5-rc1 2023-07-09 13:53:13 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.